Lighting experiment - black mask for a white NGC slab vs no mask vs image through oil

Mr_Spud

I did a lighting experiment tonight. The goal was to see how a toned small coin in an NGC slab with a white insert could be imaged the best to capture the color but with an evenly lit clear image. I’ve had some trouble with taking photos of coins in NGC slabs and have been wondering if it has something do do with the slab having a white background or because the slab itself causes too much glare and/or haziness due to the thick polycarbonate plastic.

This was with using an iPhone 12 Pro using ProRAW on autofocus with no image editing other than cropping. I tried 3 different techniques:

1) using a black mask to hide the NGCs white background
2) Using no mask
3) Using optically clear compass oil (slow evaporating volatile mineral oil) to both try to bend the light around the coin to cut the glare and to make the slab more invisible to the camera

With each technique I took photos with a generic Ott LED light alone and with additional fluorescent Ott side lights. I labeled each one below and included the original Un-cropped image so you can see the 3 different techniques. As a comparison, I also included the original auction photo which shows the color pretty good but with a big LED reflection in it and also some scans I found on the NGC website which you can’t enlarge without losing clarity but which shows the luster good.

Here’s my images, cropped shot underneath un-cropped for each technique and lighting setup

Black mask, LED + Fluorescent

Black mask, LED only

No mask, LED + Fluorescent

No mask, LED only

No mask, through oil, LED only

No mask, through oil, LED + Fluorescent

And here’s the auction photos the seller took that show the color but have LED reflection


And here’s the old NGC slab shot that show the luster good, but not the color. I cropped it to make the image bigger

So, what are your thoughts on the 3 techniques I tried. Any feedback is welcome, thanks.

LanceNewmanOCC

great experiment and presentation.

2 things off the top of my head.

a. the images are blurry because the phone isn't getting the proper focal plane? this can be tough
b. the type of lighting being used. tinker with the 3 circles overlapping while in camera view, if your iphone has those. original, vivid, warm etc. and/or try different bulbs. otts have worked great for people with actual cameras but i'm not sure the iphone can as easily circumnavigate the color and temp of those type of lights, IF your goal is to take the photography up a couple notches be essentially professional from a high-end iphone.

that said, getting images even as good as you did, which aren't too shabby, from a camera phone through a slab is pretty impressive.

experiment with more distances of camera to coin and position and heights/anlges of lights. get everything set up and look at your phone screen WHILE slowly moving the lights around like a air traffic controller and/or a crazy person waving their arms in slow motion. the goal? look for the sweet spot(s).

TurtleCat

Honestly, you can avoid the mask entirely if you switch to manual mode on the camera. Once you set the ISO and aperture to fixed values you just adjust the shutter speed until you get the lighting impact you’re trying to achieve. It’s a LOT easier in the end.

What I’d recommend to try is have the lights as parallel to the camera lens as you can and rather than adjust the lights right off, try little shims to tilt the slab slightly instead.

ricko

Since I cannot possibly critique your pictures (certainly not at my photographic skill level), I will only say I think they are really great pictures. There are only small differences between them, and I can not properly describe them. I will continue to follow the thread and probably learn something along the way. Cheers, RickO

BryceM

I'd like to comment on the lighting technique, but I'm stuck on image sharpness. Until that gets better, I wouldn't worry about lighting too much. The exposure is quite variable between the images. I think that's probably having more effect than the various masks, oil, etc. Using an iPhone it's tough. Autofocus will focus on the slab, not the coin. With a DSLR you can set white balance, manually focus, manually set exposure, and preview the image when using a tethered camera-computer connection. Shooting items behind plastic probably wasn't a major design consideration when they designed the iPhone camera.

Nice looking coin BTW.

Mr_Spud

Thanks for the feedback everybody, very much appreciated. Based on the feedback I just downloaded an
app that allows manual focusing on iPhones and I’ll figure out how to use it as the next step in the experiments. For NGC slabs and small coins I’m in agreement that the slab messes up the focus. I’ve been able to overcome that for the most part on PCGS slabs with the shot through oil technique, but not with NGC slabs.

In the meantime I just now tweaked the image of the one above that used no mask, through oil and with just LED lighting because that one looked the best to me. I tweaked it with the in phone app to adjust brightness, tint etc. and came up with this that’s about as good as it’s gonna get.

But definitely I’ll try more experiments

Kove

You can show fairly good color with lighting like you are using, and this was your stated goal.

You made one comment about luster. You won't capture luster well with your lighting. That requires point light sources. I like incandescent bulbs the best for capturing luster, but I've also seen decent results with point LEDs. But never long/bar type lights.